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Drug delivery systems based on poly(e caprolactone) for cancer treatment

Drug delivery systems based on poly(e caprolactone) for cancer treatment

Chemotherapy agents have little or no specificity over cancer cells, resulting in low therapeutic concentrations at the tumor site (a consequence of a broad systemic distribution), and severe side effects. With the aim of avoiding cancer therapy failure, several approaches such as design of new anticancer drugs, chemical engineering of conventional drugs and development of drug delivery systems have been proposed. The objective is to enhance drug localization at the tumor region (by controlling its biodistribution profile) and, therefore, to increase the anti-tumor efficacy (even in multi-drug resistant tumors), while reducing systemic side effects. One of the most promising approaches to the problem is the development of drug nanocarriers based on the polymer poly( ε -caprolactone). In this review we will focus our attention on these polymeric colloids, particularly on the most significant characteristics and formulation procedures, and on their use as nanoplatforms for the delivery of chemotherapy agents to the tumor site. Furthermore, the most recent in vitro and in vivo investigations on the subject are extensively reviewed.
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Elastin like recombinamers as smart drug delivery systems

Elastin like recombinamers as smart drug delivery systems

Doxorubicin (Dox), a widely used chemotherapeutic agent, has been bioconjugated to several ELRs. One of the first studies in this regard accomplished such conjugation by modifying the amine groups present in lysine residues of the ELR to obtain a free maleimide group, which reacted with a Dox-hydrazone complex containing an acid-labile hydrazine bond to achieve bioconjugation. Further in vitro studies performed to assess the cytotoxicity and subcellular localization of the ELR-Dox showed a similar level of squamous cell carcinoma (FaDu) cell death (less than 10% of survival after 72 h) when compared to the free drug, although different localizations were observed, with ELR- Dox being dispersed throughout the cytoplasm and free doxorubicin mostly internalized in the nucleus, suggesting different cell-death pathways in each case [51]. Another possibility involving chemical conjugation via cysteine residues was evaluated and an ELR-Dox drug system synthesized, this system allowing intracellular release of the drug as a result of an acid-labile hydrazine bond [52]. An alternative approach using the latter recombinamer involved the inclusion of a GFLG tetrapeptide linker that is recognized by lysosomal cathepsin proteases, thus permitting the release of the drug after endocytosis. A Tat domain, which is a cell-penetrating peptide (CPP) derived from the trans-activating protein found in HIV-1, was also fused to this recombinamer, theoretically improving cellular uptake of the conjugated drug. In vitro studies were performed with both non- and Dox-resistant carcinoma cell lines, resulting in a higher cytotoxicity towards drug-resistant cells in the case of the ELR-Dox when compared to the drug itself (1.4% and 31.9% resistance, respectively, in the case of breast cancer cells) [53]. Additionally, a nanoparticle-forming block copolymer ELR was used to conjugate doxorubicin via cysteine residues. Hence, 40nm particles were achieved above the Tt of the ELR, with little effect of Dox on this feature and the drug being located at the core of the nanoparticle. Tumour regression was observed in in vivo assays using a mouse colon cancer model after a single dose, which represents a great advantage with respect to the free drug [54]. Furthermore, other chemotherapeutic drugs, such as paclitaxel, have been bioconjugated and found to present the same benefits as Dox in terms of pharmacokinetics and improved solubility [55].
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Self Micro Emulsifying Drug Delivery Systems: A Strategy to Improve Oral Bioavailability

Self Micro Emulsifying Drug Delivery Systems: A Strategy to Improve Oral Bioavailability

Lipids are the important component of SMEDDS, as solubi- lization and access of the drug to the lymphatic circulation of poor water soluble drugs depend on the type and con- centration of oil used in the formulation. Digestive lipids such as triglycerides, diglycerides, fatty acids, phospholip- ids, cholesterol and other lipids based on synthetic origin offer improvement in bioavailability of the drug in contrast to the non-digestible lipids with which reduced bioavail- ability may occur due to impairment in absorption caused by retention of the fraction of administered drug in the for- mulation itself. Lipids are generally insoluble in water and are often identified by their fatty acid composition, melting point, Hydrophilic-Lipophilic Balance (HLB), and solubil- ity in non-polar organic solvents. 15,16 Lipids with low HLB
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Self Regulatory Drug Transport: An Intelligent Drug Delivery System

Self Regulatory Drug Transport: An Intelligent Drug Delivery System

As the traditional drug delivery systems (DDSs) often as- sociated with many side effects, there as an always require- ment of approaches to develop new formulations for trans- porting medicine at required level when it needed. This type of on demand basis drug delivery also called smart drug delivery or intelligent drug delivery. These novel techniques enhance the therapeutic values and also reduce various side effects. In comparison to the conventional DDSs, the smart controlled DDSs can effectively reduce the dosage frequency, while maintaining the drug concentra- tion in targeted organs/tissues for a longer period of time. In this sense, the controlled DDSs provide broad insights and fascinating properties for decreasing drug concentra- tion fluctuation, reducing drug toxicities and improving therapeutic efficacy. 1
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Venlafaxine hydrochloride transdermal patches: effect of hydrophilic and hydrophobic matrix on in vitro characteristics

Venlafaxine hydrochloride transdermal patches: effect of hydrophilic and hydrophobic matrix on in vitro characteristics

SUMMARY. Transdermal drug delivery systems of venlafaxine hydrochloride were prepared by using combination of hydrophilic (HPMC E15) and hydrophobic (ERS100 and ERL 100) polymers in 1:5, 2:4, 3:3, 4:2, 5:1 ratios by solvent casting technique with 15 % v/w propylene glycol as plasticizer. The drug permeation studies revealed that drug permeation increased proportionally with increasing HPMC ratio where ERS 100 as hydrophobic polymer but in case of ERL 100 as hydrophobic polymer proportional in- crease was not obtained this may be due to increased diffusion path length. The drug permeation kinetics followed zero order profile with diffusion mechanism. The average steady state flux obtained with HPMC: ERL 100 (3:3) was 193.2 μg/cm 2 /h and the same was increased to 257 μg/cm 2 /h with the incorporation of 5
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Bioavailability enhancement of sulpiride by self-microemulsifying drug delivery system

Bioavailability enhancement of sulpiride by self-microemulsifying drug delivery system

SUMMARY . The self-microemulsifying drug delivery system (SMEDDS) was employed to improve the bioavailability of sulpiride, a drug which is poorly soluble. The mean droplet size and emulsification time of the test formulation used for in vivo study were 9.27 ± 2.02 nm and 87 ± 5 s, respectively. When com- pared with Reference (Dogmatil®), the test formulation exhibited faster in-vitro drug release rate. The C max and AUC values of the test formulation were significantly higher than those of Reference, with an

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Formulation and evaluation of osmotic drug delivery system of ibuprofen

Formulation and evaluation of osmotic drug delivery system of ibuprofen

The IR studies of pure Ibuprofen, Ibuprofen with higher proportion of sodium chloride (20%w/w), Ibuprofen with potassium chloride (20%w/w) and Ibuprofen with sodium chloride (20%w/w) and potassium chloride (20%w/w) were carried out. Osmogens such as sodium chloride, potassium chloride are transparent to infrared radiation. Therefore no signals appeared for sodium chloride and potassium chloride. But IR spectrum of pure Ibuprofen, Ibuprofen + sodium chloride, Ibuprofen + potassium chloride and Ibuprofen + sodium chloride + potassium chloride were similar fundamental peaks and pattern which revealed that there were no significant interactions between the drug and osmogens. IR spectroscopic studies indicated that the drug is compatible with the osmogens. The granules flow property can be assessed from Angle of repose, Carr’s Compressibility Index and Hausner’s ratio. The angle of repose of all the formulations was between 29º- 33º.It proved that the flow properties of all formulations are good. The bulk density, tapped density, Compressibility index and Hausner ratio are within the acceptable limits. It indicates that the granules showed good flow character. The results are shown in Table 2.
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Pulsatile drug delivery for the treatment of nocturnal asthma: a chronopharmaceutical approach

Pulsatile drug delivery for the treatment of nocturnal asthma: a chronopharmaceutical approach

Recently pulsatile systems are gaining a lot of interest and attention, as they deliver the drug at the right site of action at right time and in right amount, thus providing spatial and tem- poral delivery and increasing patient compli- ance. A pulsatile release profile is characterized by a lag time followed by rapid and complete drug release, which is useful for the treatment of certain diseases which exhibit circadian rhythm such as asthma, gastric ulcer, hyperten- sion, ischemic heart disease and arthritis 1,2 . For

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Nanopartículas poliméricas de administración intranasal para la liberación de activos en el sistema nervioso central

Nanopartículas poliméricas de administración intranasal para la liberación de activos en el sistema nervioso central

Results. Many of the drugs employed for the treatment of neurodegenerative diseases are not capable of going through the blood-brain-barrier (BBB) and reach the brain with enough concentration, being unable to apply their therapeutic effect. That is why the idea of developing polymeric nanoparticles to be delivered through nasal delivery come out. Thanks to the use of this system, many researches have shown an improvement in the clinical utility of the drug, reducing the dose and the frequency of dosing as well as the side effects.

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Estimulacin cerebral profunda: Hacia la generacin de los dispositivos inteligentes

Estimulacin cerebral profunda: Hacia la generacin de los dispositivos inteligentes

Deep brain stimulation (DBS) is a surgical procedure approved for the treatment of select patients with movement disorders, such as Parkinson’s disease, essential tremors, and dystonia. DBS uses electricity to neuromodulate abnormal brain circuits found on these disorders to improve patient’s symptomatology. In almost 30 years, DBS has shown to be an effective therapy, however, it is not free of side effects. New technological advances have been aimed to improve clinical benefits and at the same time, minimize side effects. In this review, we discuss recent technological innovations in DBS along with the future direction of the field. We describe new DBS systems labeled “smart” devices, promising electrode designs, and newly defined methods to deliver electrical stimulation to the brain.
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Development and Evaluation of Isoniazid Loaded Silk Fibroin Microsphere

Development and Evaluation of Isoniazid Loaded Silk Fibroin Microsphere

mechanical properties and tunable degradation rates rang- ing from weeks to months in vivo due to control of excellent biocompatibility, crystallinity with low inflammatory and immunogenic response, and all aqueous material process- ing alternative to form films, gels, fibers, microspheres and sponges . For drug delivery, particularly protein drugs, silk materials exhibit controllable drug release kinetics and high encapsulation efficiency due to the crystalline beta-sheet formation. 13-16 There are several techniques available for the

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Elastin like polypeptides in drug delivery

Elastin like polypeptides in drug delivery

physiological conditions to form a local delivery depot [53]. The half-life of the resulting ELR-based coacervate at the administration site is at least 25-fold longer than for the soluble version [54]. Finally, ELRs are extremely non-inflammatory and biocompatible materials [55] and the removal of ELR-based devices when their payload is exhausted is not necessary as the biodegradation of these protein-based scaffolds follows the same natural routes as those found for structural proteins[56-58], whose degradation products, namely simple amino acids, do no present any toxicity or adverse responses[33]. Although no systematic studies on the biodegradability of ELR-based hydrogels are yet available, several parameters related to the requirements and characteristics of the body site should be taken into consideration when designing a drug-delivery device. As is the case in vitro [31], the in vivo half-life of the ELR-based hydrogel mainly depends on both enzymatic digestion and dissolution, therefore factors such as porosity, recombinamer sequence (in terms of presence of protease-sensitive sequences), and the cross-linking rate can be modified to tune their stability. For instance, the biodegradability of hydrogels obtained by coacervation may be markedly lower than that for their crosslinked counterparts as a result of dissolution. Moreover, in an environment in which ELR-based depots are exposed to a prolonged nonspecific proteolytic action, the ELRs, like all protein molecules, will be digested in a short time, whereas in less aggressive environment the half-life of such depots can exceed twelve months [33].
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Gold Nanoparticles as Drug Delivery Agents. Detoxifying the Chemotherapeutic Drug Cisplatin

Gold Nanoparticles as Drug Delivery Agents. Detoxifying the Chemotherapeutic Drug Cisplatin

In this chapter, AuNPs-cisplatin were tested in in vitro assays to evaluate the cell and DNA accumulation as well as cell viability. More importantly, in vivo assays using tumor-bearing mice were also performed. This includes evaluation of the therapeutic efficacy and evaluation of the toxicity induced by cisplatin and by AuNPs-cisplatin. Interestingly, nephrotoxicity, which is dose limiting in the clinics, was avoided only in the case of animals treated with AuNPs-cisplatin. In addition, systemic toxicity, as evaluated by body weight loss and analyzing relevant biomarkers, was also improved. Organs in which NPs are known to be accumulated (liver and spleen) were carefully examined showing no adverse long-time effects. Thus, the toxicological profile of cisplatin is clearly reduced without affecting its antitumor activity. The lack of toxicity is correlated to the modification of the pharmacokinetic properties and biodistribution of the drug by conjugation to AuNPs.
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